


Hidden Lake

by SprucePines



Category: Gravity Falls
Genre: F/M, Hand Jobs, Incest, Sibling Incest, Skinny Dipping, Twincest
Language: English
Status: Completed
Published: 2015-02-13
Updated: 2015-02-13
Packaged: 2018-03-12 03:51:35
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,140
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/3342626
Author URL: https://archiveofourown.org/users/SprucePines/pseuds/SprucePines
Summary: <blockquote class="userstuff">
              <p>Dipper and Mabel discover a lake while on a long hike in the woods. Mabel decides to take advantage of the water, even though neither of them thought to bring swimsuits. After a little cajoling, Dipper joins her.</p>
            </blockquote>





	Hidden Lake

"Dipper," Mabel groaned, drawing out the "r" for a full ten seconds, "how much longer are we gonna be out here?"

"Come on, Mabel," Dipper answered as we wove his way between a pair of oak trees. "Just a little longer. We've been coming to Grunkle Stan's for five years now, and we've never been this deep in the woods before."

"Yeah, but we've been walking all day. My dogs are barking."

"I promise, just a little more. Look, I think there's something just up ahead."

Mabel looked past Dipper. Indeed, there did appear to be something ahead. The forest canopy disappeared about a hundred yards away. Had they walked through the entire woods?

Her own curiosity piqued, Mabel caught up with her twin as they approached the edge of the trees. What greeted them there was a beautiful sight. The forest had given way to a large clearing and in the middle sat a lake of crystal clear water.

"Hey, Dipper," Mabel said as they came out into the clearing, "check it out!"

"Huh." Dipper pulled Journal #3 from his messenger bag and opened to a map of the area. "I don't see this on the map anywhere."

"Pfft, who cares?" Mabel asked. She kicked off her shoes and socks, flexing her toes to loosen them up before she trotted down to the water's edge. She tested the waters with a toe before stepping into the shallows with a satisfied "Ahhhhh."

Dipper considered for a moment. _She's right; who cares?_ Stashing the journal back in his bag, he set it down and likewise kicked off his shoes and socks. After rolling up his pant legs, he followed Mabel to the lake. As soon as his feet touched the water, he felt its cool relief course through him. _Wow, were we really hiking that long?_

He looked over at his sister, who was flapping her sweater in an attempt to fan some air onto her torso. Unable to help himself, he chuckled at the sight. Mabel narrowed her eyes at him and gave him an exaggerated pout. "Hey, you're the one who dragged me on a day long nature hike."

"I'm not the one who wears a sweater almost every day, Mabel."

She simply stared at Dipper, too hot and sweaty to think of a suitable comeback. Instead she looked out at the lake. The water looked so inviting. A grin spread on her face as an idea came to her. She spun on her heel and stepped back to where Dipper had laid his bag.

"Done already?" Dipper asked, surprised. He thought she'd want to linger here as long as possible.

"Nope, just deciding that this lake is too nice to just stand in." Lifting her sweater off in one motion, she folded it and set it by Dipper's things. "I'm going swimming."

"Swimming?" Dipper looked at the lake. He had to admit, a swim after such a long hike sounded like a really great idea. He turned towards Mabel. "But we don't have our swimsuits. Why don't we come back another day when we--"

He stopped midsentence when he saw what Mabel had in mind. She had added her shirt and skirt to the pile of clothes and was now in the process of unhooking her bra.

"Mabel, what are you doing?!"

Mabel looked at her brother. "Going swimming? Duh."

Dipper gaped at her, incredulous. "Skinny dipping?!"

"Why not? We're waaaaaay out in the middle of the woods. Who's gonna see?"

"Me, for one."

Mabel put her hands on her hips. "Dipper...it's not like we've never bathed together or anything."

"Uh, yeah, back before preschool. Pretty sure we've changed a lot since then." He couldn't stop his eyes from flashing to her nearly bare chest as he said that last part.

Mabel shook her head, muttering "Boys..." as she resumed removing her bra. Dipper quickly turned away, choosing instead to focus on the beautiful lake and not on his almost naked twin sister only about ten yards behind him. _Nope, definitely not thinking about her. Just gonna think about this lovely lake. This...lovely lake...that my sister's about to go skinny dipping in...shit..._

A moment later, Mabel sprinted past him and out into the water. He tried to close his eyes, but he wasn't quick enough to stop the afterimage of his sister's bare backside from imprinting itself on the back of his eyelids. _Dammit..._ Only after he was reasonably sure she was suitably submerged did he open his eyes.

When he opened them, he saw Mabel happily swimming out several feet. He breathed a sigh of relief. Bad enough that he'd been catching himself imagining his sister nude lately. Knowing that she actually was and only a short distance away was already causing his blood to flow downwards.

Mabel stopped and turned to face her brother. "The water's great, Dipper!" she called. "Come on!"

"Uh, no, that's alright. I'm, uh, I'm good."

"Come on, Dip, it's just us out here. No one's gonna see you but me."

"Yeah, that's what I'm afraid of," Dipper muttered.

"You say something?"

"No, just--" He sighed. _She's probably not going to quit pestering you, Dip._ Grimacing, he held up a finger to Mabel, who squealed in delight. Walking up to their things, he shucked his vest and reached for the hem of his shirt.

"Oh yeah, take it off!" his sister hooted. Dipper turned and gave her his death glare.

"Mabel, you're not helping!"

"Oh, loosen up, bro."

He turned away and pulled off his shirt. Setting it aside, he reached for the button of his pants. Steeling himself, he undid them and pushed them and his underwear down his legs. Oddly, he didn't hear any comments from the peanut gallery. Risking a glance back, he turned his head slightly. Was--was she ogling him? He dismissed that thought. _Why would she even consider ogling me?_ He looked down at his penis and was glad that it had been behaving. Still, better safe than sorry. Covering himself with both hands, he turned and awkwardly waddled to the water.

Mabel stifled a laugh as she watched Dipper. "What's the matter, Dip? Got an awkward brother boner?"

"Shut up, Mabel, I'm self conscious enough." He kept himself covered until his waist was under the surface. As he started to swim out into the lake, he had to admit that the water was really nice. He wasn't sure about the skinny dipping, but taking a swim was a great idea.

As he continued to swim and sort of acclimate himself to swimming nude, Dipper found himself beginning to relax. It really wasn't so bad. He still wasn't too keen on stripping down around Mabel, but maybe he could work around that.

Suddenly, he felt a weight press down on top of his back, accompanied by Mabel's voice shouting "Banzai!" Unable to support both their bodies, they both sank below the surface.

Once submerged and unencumbered by gravity, Dipper squirmed out from under his sister. Turning around, he got a full view of his nude twin, who was smiling at him without a care. Now feeling very warm in the water, he turned and swam furiously for the shore, hoping she couldn't glimpse his growing erection.

His head broke the surface about seventy feet from shore. He heard Mabel pop up herself a moment later. "Oh, come on, Dip," she called. "It was just a little roughhousing."

 _No, it was just a little_ naked _roughhousing,_ he thought as she swam to catch up to him.

"Dipper, wait up." Not like he had much choice right now. He couldn't very well step out of the lake with a hard on _and_ his sister this close to him. He came to a point where he could stand and still keep himself covered from the waist down. He heard Mabel stop just a few feet behind him.

"I'm sorry, Dip. I just wanted you to loosen up a bit, you know?"

Dipper sighed. He knew she wasn't being malicious or anything. He turned to face his sister, using all his willpower to keep his attention on her face and not let it drift to her breasts. "I know, Mabel. And I'm sorry for overreacting. It's just--" He paused, noticing her eyes weren't focused on his face, but were aimed downward. Much further downward.

Dipper realized that he hadn't bothered to cover himself when he turned around. He thought the water would have done a good job of keeping his nether region unseen. His body had betrayed him, though, the tip of his erection poking just above the surface. He quickly brought his hands down to cover it, which brought Mabel's attention back around.

"Whoa, I was only kidding when I said 'awkward brother boner.' Does it bother you that much going skinny dipping?"

"No. Actually, I was starting to really relax and get into it, but then you..."

"So, wait. You mean _I_ did that to you?"

Dipper blushed, too embarrassed to answer her. That was apparently answer enough for her, as the corners of her mouth curled upward slightly. _Is she...is she pleased?_

"Dipper, be honest," Mabel said, stepping closer. "Does seeing me like this...turn you on?"

Dipper opened his mouth to speak, but even saying a simple "yes" was proving a herculean task. Instead all he could do was nod. Mabel stepped closer, only about a foot away. Hesitantly, she reached forward, her eyes searching Dipper's for permission.

Dipper was lost. Here was Mabel, one of the most beautiful people he'd ever known, silently asking permission to touch him. He wanted to agree, but this was his _sister_.

His desires won out, and he took his hands away from his manhood, still at full attention. Mabel's fingers slowly ran themselves down his length, sending shivers through his body. Dipper sighed at her gentle touch, his deepest fantasy now realized.

Emboldened by her brother's reaction, she took his cock fully in hand. She was amazed at how warm it felt in her hand, how it felt both firm and soft at the same time. She was eager to explore more, but the water level was a slight interference. Keeping a gentle, yet firm grip on him, she gently guided her twin out of the water and sat him down. She sat down to his side, facing him, and slowly began sliding her hand up and down his erection.

Dipper's breath hitched and he closed his eyes. He'd masturbated himself countless times, but this was the first time another person was doing it for him. That it was his twin sister doing it only excited him more. He began to moan softly, Mabel's name occasionally escaping his lips.

While her right hand was stroking her brother's length, her left hand gently felt along Dipper's abdomen. He twitched involuntarily at her touch, but he quickly grew accustomed. She gradually explored higher, caressing his pectorals. When her fingers brushed against his nipple, she was surprised to see it react much like her own, stiffening at the stimulation.

She gently pinched and rolled it between her thumb and forefinger, gaining another moan from Dipper. She leaned forward and flicked it with her tongue. Her brother gasped again and his penis twitched in her hand. That was all the invitation she needed. She wrapped her lips around his nipple, suckling it like a newborn baby.

Dipper's breathing grew erratic. He could feel himself nearing his climax. He looked down at his sister and panted out her name.

Hearing her name, Mabel lifted her head from her brother's chest to look into his eyes. So many things were imprinted on his face; so many things he seemed to want to say to her. She only hoped he could see the same things on her face. She leaned in and kissed him, greedily sucking on his lips. Dipper responded in kind, eager to taste her.

He grunted into her lips as his erection throbbed. They broke the kiss and Mabel looked in awe at Dipper's orgasm. The first spurt shot clear up to his chest, coating the nipple she'd been suckling. The next reached the bottom of his sternum while the rest created a small pool around his belly button.

As Dipper's breathing returned to normal, all Mabel could think to say was, "Wow."

He chuckled. "Yeah. That was...really intense, actually. Thank you."

She gave him a deep kiss on the lips. "You're welcome, Dipper. But if you really want to thank me," she said, sitting back and spreading her legs, "you could always return the favor."

Dipper smiled and shifted his position. He'd have to remember to mark the lake's location on the map before they left. He had a feeling they'd be coming here a lot.


End file.
